Research and standardization activities are being conducted on inter-base station coordinated multi-point transmission and reception (CoMP) technologies in order to improve the throughput of a wireless communication system and user-experienced quality. The inter-base station CoMP is a term that collectively refers to the techniques implemented based on the coordination of transmission points or reception points that are deployed far from each other geographically.
The 3GPP LTE Release 12 specifies the base station operation and signaling in association with inter-base station CoMP (inter-eNB CoMP) as follows.
A serving base station generates a reference signal received power (RSRP) measurement report information element (IE) based on the measurement report information collected from the terminals it serves and transmits the corresponding information to neighboring base stations.
Each neighboring base station determines a COMP information IE based on the information collected from multiple base stations including the serving base station and transmits the corresponding information to the multiple base stations including the serving base station.
The CoMP information IE includes a CoMP hypothesis IE as hypothetical resource allocation information, a benefit metric related thereto, and a COMP Information Start Time IE indicating the time point when the CoMP information IE is applicable.
The CoMP hypothesis IE indicates interference-protected resource and resource with no utilization constraint by physical resource block (PRB). The benefit metric indicates the magnitude of usefulness that is predicted under the assumption that a related COMP hypothesis IE is applied. The CoMP information start time IE indicates a time point when the CoMP information IE is applicable.
The serving base station may perform radio resource management (RRM) including inter-base station CoMP based on the received CoMP information IE. For example, the serving base station may allocate radio resources to the terminal and perform base station-terminal link adaptation based on the CoMP information IE.
However, there may be a backhaul delay between the serving base station and the neighboring base station, and a backhaul delay may restrict the data transmission chances of the serving base station more than necessary or make the base station perform link adaptation passively, resulting in radio resource management inefficiency.